Like a polished and mobile-first Craigslist, New York City-based Bondsy is building a social network that lets you trade just about anything with your friends. No strangers allowed.

Bondsy graduated a year ago from TechStars NYC as a simple social network for selling stuff from your phone — but since then it has evolved into a tool that could help you reconnect with your friends in the real world. The company soft-launched in January, but today it’s officially debuting to the world with a marketing push.

So far, people have used the service to trade handwritten letters in exchange for handwritten replies, gadgets for homemade dinners, and my favorite example, bacon for coffee beans.

Diego Zambrano, Bondsy’s founder, CEO, and serious beard curator, tells me that he learned a lot simply by letting users approach the social network as they saw fit.

“If you give tools that allow people to be creative, people get very creative,” Zambrano said in an interview. “If we go beyond transaction and become a platform that allows people to express themselves, that creates a true bond between people. Those are the most exciting things for us.”

The company’s free iPhone app lets you create a trade listing for just about anything. Maybe you want to get rid of your old records, maybe you’re trying to sell a piece of furniture, or maybe you just want to have dinner with your friends. Bondsy appears to be trying to recreate social connections in the real world that were common before social networks pushed us to the digital world.

Unlike most other marketplaces, Bondsy takes a freeform approach to price tags. While there are plenty of Bondsy posts asking for cash, the ones that truly stand out ask for something interesting, like a lunch or dinner. It’s a good way for you to reconnect with people you haven’t seen in a while, but it could be used for just about anything.

In Brazil, Bondsy users are using the social network to sell cars. In China, it’s being used to set up intriguing gamified challenges. Zambrano embraces all of it.

“My take is that we’ve been going through this whole phase of trying to make everything frictionless, and I noticed that the most meaningful experience I’ve had were the ones that actually had some friction,” he said.

To support his move from Brazil to New York City several years ago, Zambrano sold all of his personal possessions on Flickr. While he was able to get rid of his junk, what struck him most about that experience was meeting up with friends to complete the transactions. That sparked the idea to create Bondsy.

To encourage creativity, Bondsy places a premium on privacy. The company decided to build its own social graph, rather than latch onto an existing network like Facebook and Twitter, because it didn’t trust the way other companies managed their privacy settings.

“By building the way we’re building, it directly changes what people share,” Zambrano said. “It directly changes how open people are.”

Bondsy has received seed funding from Thrive Capital, Betaworks, Chris Dixon, David Tisch, and others.

“What is interesting about leaving Bondsy open and not very structured is that we allow our users to define how they want to use it,” Zambrano said. “It’s a sin to kill these possible behaviors by creating too much structure.”